Final answer:
Josh will turn to the firefighter to let him know about the fire.
Step-by-step explanation:
Based on the concept of informational social influence, it is most likely that Josh will turn to the firefighter to let him know about the fire. This is because the firefighter's profession and expertise make them a credible source of information in this situation. Josh is likely to rely on the firefighter's knowledge and take action based on their response.